Image forming apparatus

ABSTRACT

An image forming apparatus includes an image reading unit, an image forming unit, a discharge unit, and a discharge tray. The image reading unit is configured to read a document placed on a document placement table by moving and scanning of a scanning body in a sub-scanning direction. The image forming unit is configured to form an image read by the image reading unit on a paper sheet. The discharge unit is configured to discharge the paper sheet on which an image is formed by the image forming unit to a direction perpendicular to the sub-scanning direction. The discharge tray is on which the paper sheet from the discharge unit is to be placed with a space portion at a lower side of the image reading unit. A bottom surface of a housing of the image reading unit facing the discharge tray is constituted of a first surface and a second surface. The first surface is a surface at a front side of the discharge unit in a discharging direction and high with respect to the discharge tray. The second surface is a surface at a back side of the discharge unit in the discharging direction lower than the first surface with respect to the discharge tray. A pulling member and/or a movable wiring are/is arranged at an upper side of the second surface inside the housing. The pulling member is configured to move the scanning body back and forth in the sub-scanning direction. One end portion of the movable wiring is secured to the scanning body.

This application is a divisional of U.S. patent application Ser. No.15/013,668, filed Feb. 2, 2016, which is a divisional of U.S. patentapplication Ser. No. 14/391,254, filed Oct. 8, 2014, which is the U.S.national phase of International Application No. PCT/JP2013/060488 filed5 Apr. 2013 which designated the U.S. and claims priority to JapanesePatent Application No. 2012-093122 filed 16 Apr. 2012, the entirecontents of each of which are hereby incorporated by reference.

TECHNICAL FIELD

The present invention relates to an image forming apparatus of anin-body paper discharging type, more specifically, relates to an imageforming apparatus with a structure where a paper sheet on which an imagehas been formed by an image forming unit is discharged in a directionperpendicular to a sub-scanning direction, a movement direction of ascanning body.

BACKGROUND ART

Recently, demands of space-saving, downsizing, and thinning of an imageforming apparatus have been further increased. In response to thesedemands, it is possible to thin an image forming apparatus of an in-bodypaper discharging type that includes a discharge tray between an imagereading unit (a scanner unit) and an image forming unit by narrowingdown its sheet discharge space. However, narrowing down the sheetdischarge space causes a problem that a paper sheet is difficult to beextracted.

In particular, assume that a surface of an apparatus main body facing auser standing position is a front surface side. With the image formingapparatus with an in-body paper discharge structure where a sheetdischarge space opens to the front surface side of the apparatus mainbody and a paper sheet is discharged from a back surface side (a backside) to the front surface side (the front side) of the apparatus mainbody, only a distal end part of the paper sheet to be discharged is seenfrom the opening of the sheet discharge space. Accordingly, there is aproblem that narrowing the sheet discharge space making the extractionof the paper sheet more difficult.

Therefore, image forming apparatuses disclosed in Patent Literatures 1and 2 are provided as one method for solving this problem.

The image forming apparatus disclosed in Patent Literature 1 is an imageforming apparatus of the in-body paper discharging type with an openingfor a sheet discharge space at a front side. As illustrated in FIG. 2 ofPatent Literature 1, a recording paper creating unit (an image formingunit) is arranged so as to project to the front side with respect to animage reading unit (a scanner unit). Moreover, a lower surface at thefront side of the image reading unit is formed to an inclined surfaceinclining so as to expand toward the opening.

Similarly, the image forming apparatus disclosed in Patent Literature 2is an image forming apparatus of the in-body paper discharging type withan opening for a sheet discharge space at a front side. As illustratedin FIG. 3 of Patent Literature 2, the image forming apparatus includesan inclined portion (or a step) between a lower-surface-front-portionsupporting unit, which is a top board, and a lower-surface-rear-portionsupporting unit (a lower projecting portion supporting unit) thatsupport an image reading unit (an image scanner). The image formingapparatus where the lower-surface-front-portion supporting unit isformed at a higher position than the lower-surface-rear-portionsupporting unit using this inclined portion (or the step) is disclosed.

CITATION LIST Patent Literature

PATENT LITERATURE 1: Japanese Unexamined Patent Application PublicationNo. 2004-118210

PATENT LITERATURE 2: Japanese Unexamined Patent Application PublicationNo. 2006-121721

SUMMARY OF INVENTION Technical Problem

However, the image forming apparatus of Patent Literature 1 has astructure that discharges a paper sheet from a front surface side (anopening side) of an apparatus main body to a back surface side (a backside) of the apparatus main body. Accordingly, regardless of a papersheet size, a rear end portion of the discharged paper sheet alwayspositions at the opening, which is at the front side. Therefore, it canbe said that the paper sheet can be easily extracted even if the lowersurface at the front side of an image reading unit is not formed at aninclined surface. With the image forming apparatus of Patent Literature1, since a recording paper creating unit (an image forming unit) isarranged so as to project to the front side with respect to an imagereading unit (a scanner unit), resulting in going against downsizing ofthe apparatus.

The image forming apparatus of Patent Literature 2 has a structure thatdischarges a paper sheet from a right side at a front surface of anapparatus main body to a left side at the front surface of the apparatusmain body (that is, parallel along an inclined portion and a step).Accordingly, regardless of a paper sheet size, the entire side endportion of the discharged paper sheet always positions at an opening. Inthis meaning, it can be said that the paper sheet can be easilyextracted comparatively even if a lower surface at the front side of animage reading unit is not formed at the inclined portion and the step.

On the other hand, with an image forming apparatus with an in-body paperdischarge structure where a sheet discharge space opens to a frontsurface side of an apparatus main body and that discharges a paper sheetfrom a back surface side (a back side) to a front surface side (a frontside) of the apparatus main body, even if the inclined surface and thestep disclosed in Patent Literatures 1 and 2 are disposed, only thedistal end part of the paper sheet to be discharged is seen from theopening for the sheet discharge space. This does not sufficiently solvethe problem of difficulty in the extraction of the paper sheet. Inparticular, in the case of a small-sized paper, such as a postcard, thedistal end portion of the paper sheet positions at the back side fartherthan the inclined surface. Accordingly, it cannot be said that theproblem of difficulty in the extraction of the paper sheet issufficiently solved only by disposing the inclined surface and the step.

On the other hand, as another method for expanding a discharge space,thinning the image reading unit is considered. However, in the casewhere a scanning body (a scanner body) and a circuit board inside of theapparatus main body are coupled with a movable wiring cable (a flatcable), a thickness of the image reading unit needs to be secured by atleast a thickness of the wiring cable in a width direction.Additionally, a position at which a pulling member for moving thescanning body back and forth in a sub-scanning direction is arrangedneeds to be secured. Accordingly, this wiring cable and pulling memberbecome a problem for thinning the image reading unit.

The present invention has been made to solve these problems, and itsobject is to provide an image forming apparatus with an in-body paperdischarge structure where a sheet discharge space opens to a frontsurface side of an apparatus main body and that discharges a paper sheetfrom the back surface side (the back side) to the front surface side(the front side) of the apparatus main body. The image forming apparatusachieves easily extracting the paper sheet discharged on a dischargetray by expanding the sheet discharge space (that is, a height directionis heighten), being unaffected by an influence of the wiring cable andthe pulling member.

Solutions to the Problems

To solve the above-described problems, an image forming apparatus of thepresent invention is an image forming apparatus that includes an imagereading section, an image forming section, a discharge section, and adischarge tray. The image reading section is configured to read adocument placed on a document placement table by moving and scanning ofa scanning body in a sub-scanning direction. The image forming sectionis configured to form an image read by the image reading section on apaper sheet. The discharge section is configured to discharge the papersheet on which an image is formed by the image forming section to adirection perpendicular to the sub-scanning direction. The dischargetray is on which the paper sheet from the discharge section is to beplaced with a space section at a lower side of the image readingsection. A bottom surface of a housing of the image reading sectionfacing the discharge tray is constituted of a first surface and a secondsurface. The first surface is a surface at a front side of the dischargesection in a discharging direction and high with respect to thedischarge tray. The second surface is a surface at a back side of thedischarge section in the discharging direction lower than the firstsurface with respect to the discharge tray. A pulling member and/or amovable wiring are/is arranged at an upper side of the second surfaceinside the housing. The pulling member is configured to move thescanning body back and forth in the sub-scanning direction. One endportion of the movable wiring is secured to the scanning body. Morespecifically, the bottom surface of the housing is segmented into thefirst surface and the second surface with a stepped section formed alongthe sub-scanning direction.

With the above-described configuration, the pulling member (a belt, apulley, or a similar component) and the movable wiring (a flat cable ora similar cable) are arranged inside the housing at the upper side ofthe second surface. Therefore, a height of the first surface, which is abottom surface of the image reading section, from the discharge tray canbe raised up to a height restricted by the scanning body. Further, byraising the bottom of the first surface, the discharge space on thedischarge tray is expanded particularly in the height direction.Accordingly, even if a small-sized paper sheet is discharged on thedischarge tray, the paper sheet discharged to the back side of thedischarge tray (the discharge section side) can be easily taken out.Additionally, the apparatus itself can be downsized.

In the image forming apparatus of the present invention, the dischargesection may be arranged at a lower side of the first surface or a lowerside of the second surface. More specifically, the discharge section maybe arranged close to the stepped section.

In the image forming apparatus of the present invention, the firstsurface may include a plurality of rib pieces. The plurality of ribpieces extend in a paper discharging direction perpendicular to thesub-scanning direction.

Thus, by disposing the plurality of rib pieces at the first surface,even if the paper sheet discharged from the discharge section abuts onthe first surface and is worn down, the paper sheet abuts on the ribpieces before abutting on the first surface, allowing reducing a rubsound. Disposing the rib pieces allows preventing a paper jam caused bythe distal end of the paper sheets discharged from the discharge sectionabutting on and being got caught on the first surface. This also canprevent the discharged paper sheets from being irregularly loaded on thedischarge tray.

In the image forming apparatus of the present invention, a projectionprojecting inward of the housing section may be disposed along thesub-scanning direction. The projection is disposed at an end portion ofthe first surface close to the discharge section. With thisconfiguration, by disposing the projection at the end portion close tothe discharge section on the first surface, the strength of the bottomsurface of the housing for the image reading section can be enhanced.

In the image forming apparatus of the present invention, the projectionmay be disposed at the stepped section. With this configuration,disposing the projection at the stepped section allows enhancing thestrength of the bottom surface of the housing for the image readingsection.

In the image forming apparatus of the present invention, the projectionis a guiding section configured to guide the scanning body in thesub-scanning direction. At a bottom surface of the scanning body, aguided section may be disposed to be guided by the guiding section tomove back and forth in the sub-scanning direction. With thisconfiguration, the use of the projection as the guiding section allowsdoubling two functions as a function for preventing a deterioration of astrength of the housing and a guiding function of the scanning body.

In the image forming apparatus of the present invention, the guidedsection may be a concaved groove section formed along the sub-scanningdirection engaging with and slidably in contact with the projection. Thesimple engaging structure, the projection and the concaved groovesection, allows smoothly guiding the scanning body.

In the image forming apparatus of the present invention, the projectionis a concaved groove section where a bottom surface side of the housingis concaved upward along the sub-scanning direction. The concaved groovesection may include a static eliminating brush. With this configuration,disposing the static eliminating brush at the concaved groove sectionallows reliably eliminating static electricity on the paper sheetdischarged from the discharge section.

Advantageous Effects of Invention

According to the present invention, the pulling member and the movablewiring are arranged inside the housing at the upper side of the secondsurface. Therefore, a height of the first surface, which is a bottomsurface of the image reading unit, from the discharge tray can be raisedup to a height restricted by the scanning body. Further, by raising thebottom of the first surface, the discharge space on the discharge traycan be expanded in the height direction. Accordingly, even if asmall-sized paper sheet is discharged on the discharge tray, the papersheet discharged to the back side of the discharge tray (the dischargeunit side) can be easily taken out. Additionally, the apparatus itselfcan be downsized (in particular, thinned).

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a perspective view of an image forming apparatus of thepresent invention.

FIG. 2 is a schematic cross-sectional view of when the image formingapparatus of the present invention is viewed from a side surface and aschematic cross-sectional view taken along the line I-I of FIG. 1.

FIG. 3A is a perspective view of an image capturing housing unit.

FIG. 3B is a perspective view of the image capturing housing unit.

FIG. 4 is a perspective view of when the image capturing housing unit isviewed from a bottom surface side.

FIG. 5 is a cross-sectional view taken along the line II-II of FIG. 3A.

FIG. 6 is an enlarged cross-sectional view of a main part of FIG. 5.

FIG. 7 is an enlarged cross-sectional view of a main part illustratinganother example of a formation position of a projection.

FIG. 8 is an enlarged cross-sectional view of a main part illustratingan application example of the image forming apparatus of the presentinvention.

FIG. 9 is an enlarged cross-sectional view of a main part illustratinganother exemplary constitution of an arranged location of a paper sheetdischarge port (a discharge roller pair).

DESCRIPTION OF EMBODIMENTS

Embodiments of the present invention will be described below byreferring to the accompanying drawings.

FIG. 1 is a perspective view of an image forming apparatus of thepresent invention. FIG. 2 is a schematic cross-sectional view of whenthe image forming apparatus of the present invention is viewed from aside surface (a schematic cross-sectional view taken along the line I-Iof FIG. 1). FIG. 3A and FIG. 3B are perspective views of an imagecapturing housing unit. Note that, in the embodiment, the illustrationof an original reading apparatus that reads documents in automaticfeeding is omitted.

An image forming apparatus A illustrated in FIG. 1 and FIG. 2 is animage forming apparatus of an in-body paper discharging type. The imageforming apparatus A includes an in-body paper discharge space portion 13between an image capturing housing unit 11 and an image forming housingunit 12 of an apparatus main body 10. The in-body paper discharge spaceportion 13 has a U shape in a cross section. Assume that an opposedsurface of the apparatus main body 10 facing a user standing position asa front surface side. The in-body paper discharge space portion 13 isopen to the front surface side of the apparatus main body 10. The imageforming apparatus A has a structure that discharges a paper sheet from aback surface side (a back side) to the front surface side (a front side)of the apparatus main body 10 (a Y direction in the drawing). A paperfeed tray 31 also has a structure of being extracted from the frontsurface side of the apparatus main body 10 in the Y direction.

A document placement table glass 21 on which the document is placed isdisposed at the top of the image capturing housing unit 11. The documentplacement table glass 21 is made of a transparent glass. A scanning body(an optical unit) 22, a pulling member 23, and a movable wiring 24 aredisposed at the inside of the image capturing housing unit 11 at thelower portion of the document placement table glass 21. The scanningbody 22 reads the documents. The pulling member 23 moves the scanningbody 22 back and forth in a sub-scanning direction X (that is, adirection perpendicular to a paper discharging direction Y). One endportion of the movable wiring 24 is coupled to and secured to thescanning body 22. The other end portion of the movable wiring 24 iscoupled to and secured to a circuit board (not illustrated) disposedinside of the apparatus main body 10. The entire movable wiring 24formed of a flat cable or a similar cable is flexibly disposed. That is,the image forming apparatus A according to the embodiment is arrangedsuch that a scanning direction X of the scanning body 22 isperpendicular to the paper discharging direction Y.

The pulling member 23 includes an idler pulley 23 a, a drive pulley 23b, and an endless belt 23 c. The idler pulley 23 a and the drive pulley23 b are arranged adjacent to both end portions in the sub-scanningdirection X. The belt 23 c is bridged across these pulleys 23 a and 23b. The scanning body 22 is secured to the belt 23 c. The drive pulley 23b coordinates with a driving motor (not illustrated) via a pulley gear23 d or a similar gear. However, since this constitution of the pullingmember 23 is a conventionally known constitution, the detaileddescription will not be further elaborated here. Since variouswell-known conventional constitution is also applicable to theconstitution of the scanning body 22 (an integrally combined structureof an optical unit and a unit case that houses the optical unit or asimilar unit), the detailed description of such combined structure willnot be further elaborated here.

As illustrated in FIG. 1, FIG. 3A, and FIG. 3B, a slit portion 11 b forextracting a cable is formed at approximately center of a sidewall 11 aat a back surface side (a back side) inside of the image capturinghousing unit 11 in the sub-scanning direction X. The movable wiring(hereinafter referred to as the movable wiring cable) 24 whose other endportion is coupled to the circuit board (not illustrated) is guided tothe lateral direction such that a flat surface of the movable wiringcable 24 stands vertically from the slit portion 11 b. The guidedmovable wiring cable 24, as illustrated in FIG. 1 and FIG. 3A, isextended to a back surface 22 a side via an end portion of the scanningbody 22, and then is folded back to a U shape at the back surface 22 aside. A folded-back distal end portion 24 a is secured to the endportion of the back surface 22 a and is electrically connected to aninternal optical unit (CIS: Contact Image Sensor) (not illustrated).

The movable wiring cable 24 thus wired, as a deformation process of themovable wiring cable 24 illustrated in FIG. 3B, when the scanning body22 is at a scanning start position Rs, the movable wiring cable 24extends almost in a straight line excluding a secured portion of thefolded-back distal end portion 24 a. When the scanning body 22 movesfrom the scanning start position Rs in a scanning direction X1 andreaches around the center portion (a position denoted by Rm in FIG. 3B),the movable wiring cable 24 is deformed to a loop shape drawing a largering. Further, when the scanning body 22 moves in the scanning directionX1 and reaches a scanning end position Re, the movable wiring cable 24excluding the secured part of the folded-back distal end portion 24 adeforms so as to extend in a gentle curve shape. When the scanning body22 ends the scanning and returns to the scanning start position Rs in ascanning direction X2, the movable wiring cable 24 experiences adeformation process reverse to the above-described process.

The image forming apparatus A thus constituted is a color image formingapparatus that forms multi-color and single-color images on a sheet suchas a recording paper sheet (hereinafter referred to as a paper sheet) Paccording to image data transmitted from the outside. The apparatus mainbody 10 includes an original reading apparatus (not illustrated) at theupper portion. The image forming housing unit 12 includes an imageforming unit 20 and a paper sheet conveyance system 30.

The image forming unit 20 includes an exposure unit 1, a plurality ofdeveloping units 2, a plurality of photosensitive drums 3, a pluralityof cleaning units 4, a plurality of charging units 5, an intermediatetransfer belt unit 6, a fixing unit 7, and a plurality of tonercartridge units 8.

The paper sheet conveyance system 30 includes a paper sheet conveyancepassage S, the paper feed tray 31, a paper feeder 32, and a dischargetray 40. The paper feed tray 31 houses a paper sheet P. The paper feeder32 supplies the paper sheet P housed in the paper feed tray 31 to thepaper sheet conveyance passage S.

The discharge tray 40 is disposed upward of the image forming unit 20 ofthe apparatus main body 10. The discharge tray 40 accumulates theimage-formed (printed) paper sheet P in a facedown manner.

The paper feeder 32 has a constitution that supplies the paper sheet Pto be housed in the paper feed tray 31 to the paper sheet conveyancepassage S. The paper feeder 32 includes a feed roller 33, a separationconveyance roller 32 a, a separating member 32 b, an elevation driveunit (not illustrated), and a sheet supply drive unit (not illustrated).The elevation drive unit drivingly moves up and down a rotating plate 34at the paper feed tray 31 with an elevating mechanism unit 35. The sheetsupply drive unit rotatably drives the separation conveyance roller 32 aand the feed roller 33.

The image forming apparatus A handles image data corresponding to colorimages using a plurality of colors (here, respective colors of black(K), cyan (C), magenta (M), and yellow (Y)). Accordingly, the pluralityof respective developing units 2, photosensitive drums 3, cleaning units4, charging units 5, and toner cartridge units 8 are set (here, fourunits of black, cyan, magenta, and yellow are provided for each) to forma plurality of kinds (here, four kinds) of images corresponding to therespective colors. These units constitute a plurality of image stations(here, four stations).

The exposure unit 1 is constituted as a laser scanning unit (LSU) with alaser emitting portion and a reflective mirror. The exposure unit 1exposes the respective charged photosensitive drums 3 corresponding toinput image data. This forms electrostatic latent images correspondingto the image data on surfaces of the respective photosensitive drums 3.

The toner cartridge unit 8 is a unit that houses toner, and supplies thetoner to a developer tank of the developing unit 2.

The developing unit 2 uses four colors (Y, M, C, and K) of toners tovisualize the electrostatic latent images formed on respectivephotosensitive drums 3. The cleaning unit 4 removes and recovers thetoner remaining on the surface of the photosensitive drum 3 afterdevelopment and transfer of the image. The charging unit 5 uniformlycharges the surface of the photosensitive drum 3 at a predeterminedelectric potential.

The intermediate transfer belt unit 6 arranged above the photosensitivedrum 3 includes an intermediate transfer belt 61, an intermediatetransfer belt drive roller 62, an intermediate transfer belt drivenroller 63, a plurality of intermediate transfer rollers 64, and anintermediate transfer belt cleaning unit 65. The intermediate transferbelt 61 acts as an intermediate transfer body.

Four of the intermediate transfer rollers 64 are disposed correspondingto the respective colors of Y, M, C, and K. The intermediate transferbelt drive roller 62 stretches the intermediate transfer belt 61 and isrotatably driven along with the intermediate transfer belt driven roller63 and the intermediate transfer roller 64 to move the intermediatetransfer belt 61 around in a movement direction (a direction of an arrowM in FIG. 2).

The toner images with respective colors formed on the respectivephotosensitive drums 3 are sequentially transferred to be overlaid onthe intermediate transfer belt 61. This forms a color toner image (amulti-color toner image) on the surface of the intermediate transferbelt 61.

The toner image is transferred from the photosensitive drum 3 to theintermediate transfer belt 61 by the intermediate transfer roller 64 incontact with a back side of the intermediate transfer belt 61.

As described above, the toner images are visualized on the respectivephotosensitive drums 3 corresponding to the respective hues, andlaminated on the intermediate transfer belt 61. The toner imageslaminated on the intermediate transfer belt 61 are moved by rotation ofthe intermediate transfer belt 61. The toner images are then transferredon the paper sheet P with a transfer roller 66. The transfer roller 66is arranged at a position at which the paper sheet P is in contact withthe intermediate transfer belt 61.

The intermediate transfer belt cleaning unit 65 removes and recovers thetoner remaining on the intermediate transfer belt 61.

The apparatus main body 10 includes the S-shaped paper sheet conveyancepassage S. The paper sheet conveyance passage S transmits the papersheet P on the paper feed tray 31 to the discharge tray 40 via the imageforming unit 20. Along the paper sheet conveyance passage S, respectiveconveyance members such as a conveyance roller pair 14, aprior-to-registration roller pair 15, a registration roller pair 16, ahot roller 71 and a pressure roller 72 in the fixing unit 7, and adischarge roller pair 41 are arranged.

The fixing unit 7 is arranged in the apparatus main body 10 at a backsurface 13 a side of the in-body paper discharge space portion 13 formedinto a U shape in cross section. The fixing unit 7 receives the papersheet P on which the toner image has been transferred and sandwiches thereceived paper sheet P between the hot roller 71 and the pressure roller72 for conveyance. The discharge roller pair 41 arranged adjacent to theback surface 13 a of the in-body paper discharge space portion 13discharges the paper sheet P after fixation of the toner images withrespective colors from a paper sheet discharge port (a discharge unit)42 formed at the back surface 13 a of the in-body paper discharge spaceportion 13 on the discharge tray 40 in the paper discharging directionY.

In the case where not only a front surface of the paper sheet P butduplex image formation is performed, after the fixing unit 7 fixes theimage on the front surface of the paper sheet P, in the process of thepaper sheet P being conveyed by the discharge roller pair 41 in thepaper sheet conveyance passage S, the discharge roller pair 41 isstopped and inversely rotated. Next, the paper sheet P is passed throughto a front-back reverse path Sr, the front and back of the paper sheet Pis reversed, and the paper sheet P is again guided to an upstream sidewith respect to the registration roller pair 16 in a supply direction N(in this example, the upstream side of the prior-to-registration rollerpair 15). Then, similar to the front surface of the paper sheet P, animage is recorded and fixed on the back surface of the paper sheet P,and finally the paper sheet P is discharged to the discharge tray 40.

The overall constitution of the image forming apparatus A is describedabove.

The following describes the constitution of the image capturing housingunit 11, which is a feature of the present invention, with reference toFIG. 1 to FIG. 6. Note that FIG. 4 is a perspective view of when theimage capturing housing unit 11 is viewed from a bottom surface side,FIG. 5 is a cross-sectional view taken along the line II-II of FIG. 3A,and FIG. 6 is an enlarged cross-sectional view of a main part of FIG. 5.

In the image forming apparatus A of the present invention, a bottomsurface 50 of the image capturing housing unit 11 opposed to thedischarge tray 40 is configured as follows. At the front side of thedischarge tray 40 in the discharging direction the bottom surface 50 ofthe image capturing housing unit 11 is configured as a first surfacehigher than the discharge tray 40. At the rear side of the dischargetray 40 in the discharging direction the surface of the bottom surface50 is configured as a second surface lower than the first surface withrespect to the discharge tray 40.

More specifically, the image capturing housing unit 11 of thisembodiment is constituted as follows. The bottom surface 50 (see FIG. 4)facing the discharge tray 40 is segmented into a first surface 51 and asecond surface 52 with a stepped portion 53 formed along thesub-scanning direction X. The first surface 51 at the front side of thepaper sheet discharge port 42, which is a discharge unit, in thedischarging direction (namely, the front surface side of the apparatusmain body 10) is arranged so as to be disposed at a higher position thanthe second surface 52 at the read side of the paper sheet discharge port42, which is a discharge unit, in the discharging direction (namely, theback surface side of the apparatus main body 10) with respect to thedischarge tray 40. That is, the first surface 51 is arranged away fromthe discharge tray 40 more than the second surface 52. The paper sheetdischarge port 42 (namely, the discharge roller pair 41) is arranged atthe lower side of the second surface 52 and adjacent to the steppedportion 53 (namely, close to the stepped portion 53).

Then, according to the embodiment, the pulling member 23 and the movablewiring cable (the flat cable or a similar cable) 24 are arranged at theupper side of the second surface 52 in the image capturing housing unit11. The pulling member 23 moves the scanning body 22 back and forth inthe sub-scanning direction X.

According to this constitution, it is only necessary that only thescanning body 22 be disposed at the upper side of the first surface 51inside of the image capturing housing unit 11. Therefore, a height ofthe first surface 51, which is a bottom surface of the image capturinghousing unit 11, from the discharge tray 40 can be raised up to a heightrestricted by the scanning body 22. By raising the bottom of the firstsurface 51, the in-body paper discharge space portion 13 on thedischarge tray 40 is expanded particularly in the height direction.Accordingly, even if a small-sized paper sheet is discharged on thedischarge tray 40, the paper sheet discharged to the back side of thedischarge tray 40 (the back surface 13 a of the in-body paper dischargespace portion 13) can be easily taken out. Additionally, the apparatusitself can be downsized.

With the image forming apparatus A of this embodiment, the projection 54projecting inward of the image capturing housing unit 11 is disposedalong the sub-scanning direction X. The projection 54 is disposed at anend portion of the first surface 51 close to the paper sheet dischargeport 42. Thus, the first surface 51 includes the projection 54 at theend portion close to the paper sheet discharge port 42. This allowsfurther improving a strength of the bottom surface of the imagecapturing housing unit 11.

The projection 54 also serves as a guiding portion that guides thescanning body 22 in the sub-scanning direction X. Accordingly, a guidedportion 26 is disposed at a bottom surface (more specifically, thebottom surface of the unit case housing the optical unit) 22 bapproximately center portion of the scanning body 22 in the widthdirection (the paper discharging direction Y). The projection 54, whichis a guiding portion, guides the guided portion 26 to move the guidedportion 26 back and forth in the sub-scanning direction X. In thisembodiment, this guided portion 26 is a concaved groove unit formedslidably in contact with the projection 54 so as to be fitted to andengaged with the projection 54 along the sub-scanning direction X. Withthis configuration, the use of the projection 54 as the guiding portiondoubles two functions as a function for preventing a deterioration of astrength of the image capturing housing unit 11 and a guiding functionof the scanning body 22. The simple engaging structure, the projectionand the concaved groove portion, allows smoothly guiding the scanningbody 22.

In this embodiment, a plurality of rib pieces 56 (see FIG. 4) aredisposed at the first surface 51. The plurality of rib pieces 56 extendin the paper discharging direction Y, which is perpendicular to thesub-scanning direction X. As shown in FIG. 4, the plurality of ribpieces are formed at different intervals.

Thus, by disposing the plurality of rib pieces 56 at the first surface51, even if the paper sheet discharged from the paper sheet dischargeport 42 abuts on the first surface 51 and is worn down, the paper sheetabuts on the rib pieces 56 before abutting on the first surface 51,allowing reducing a rub sound. Disposing the rib pieces 56 allowspreventing the discharged paper sheets from being irregularly loaded onthe discharge tray caused by the distal end of the paper sheetsdischarged from the paper sheet discharge port 42 abutting on and beinggot caught on the first surface 51. This also can prevent a paper jam ora similar problem caused by the distal end of the paper sheets abuttingon the first surface 51.

FIG. 7 illustrates another example of a formation position of theprojection 54. That is, in the above-described example, even if thestepped portion 53 and the projection 54 are arranged closely, therespective stepped portion 53 and projection 54 are individually formed.However, in the example of FIG. 6, the stepped portion 53 is run so asto directly project to the inside of the image capturing housing unit11, and then is folded back downward in a U shape in cross section, thusthe projection 54 is formed. That is, the stepped portion 53 is used asone sidewall of the projection 54. With this configuration, disposingthe projection 54 at the stepped portion 53 (that is, integrally formingthe projection 54 and the stepped portion 53), the strength of thebottom surface of the image capturing housing unit 11 can be enhanced.

In this embodiment, a concaved groove portion 54 a is disposed at thebottom surface side of the projection 54. The concaved groove portion 54a is concaved upward at the first surface 51 side along the sub-scanningdirection X. As illustrated in FIG. 8, using this concaved grooveportion 54 a, a static eliminating brush 57 may be disposed at theconcaved groove portion 54 a. In this case, the paper sheet dischargeport 42 and the discharge roller pair 41 are preferred to be disposednear the stepped portion 53 (namely, close to the stepped portion 53).In order that the paper sheet P discharged from the paper sheetdischarge port 42 is reliably in contact with the static eliminatingbrush 57 and then is placed on the discharge tray 40, a distance fromthe concaved groove portion 54 a to the paper sheet discharge port 42and the discharging direction of the paper sheet P from the paper sheetdischarge port 42 may be designed in advance. With this configuration,disposing the static eliminating brush 57 at the concaved groove portion54 a allows reliably eliminating static electricity on the paper sheetdischarged from the paper sheet discharge port 42.

In the above-described embodiment, the paper sheet discharge port 42(namely, the discharge roller pair 41) is arranged at the lower side ofthe second surface 52 near the stepped portion 53. However, asillustrated in FIG. 9, the paper sheet discharge port 42 (namely, thedischarge roller pair 41) can be arranged at the lower side of the firstsurface 51 near the stepped portion 53.

Furthermore, in the above-described embodiment, disposing the steppedportion 53 provides a difference in height with respect to the dischargetray 40 between the first surface 51 and the second surface 52. However,without such stepped portion, forming the first surface 51 and thesecond surface 52 into an continuous inclined surface allows configuringthe surface at the front side of the discharge tray 40 in thedischarging direction as the first surface higher than the dischargetray 40 and the surface at the rear side of the discharge tray 40 in thedischarging direction as the second surface lower than the first surfacewith respect to the discharge tray 40. The inclination angle withrespect to the discharge tray 40 may be the same from the first surfaceto the second surface. The inclination angle of the first surfacerelative to the discharge tray 40 may be formed large, and theinclination angle of the second surface relative to the discharge tray40 may be formed small (that is, the bottom surface 50 is bent at aboundary part between the first surface and the second surface).

The above-disclosed embodiments are to all intents and purposes merelyillustrative and should not be construed as limiting. The scope of thepresent invention is defined by the claims and is not in any wayrestricted by the descriptions of the specification. Furthermore, allvariations within the meaning and range of equivalency of the claimsfall within the scope of the present invention.

The present invention can be embodied and practiced in other differentforms without departing from the spirit and essential characteristics ofthe present invention. Therefore, the above-described embodiments areconsidered in all respects as illustrative and not restrictive. Thescope of the invention is indicated by the appended claims rather thanby the foregoing description. All variations and modifications fallingwithin the equivalency range of the appended claims are intended to beembraced therein.

This application claims priority on Japanese Patent Application No.2012-093122 filed in Japan on Apr. 16, 2012, the entire content of whichis incorporated herein by reference.

INDUSTRIAL APPLICABILITY

The present invention is effective to an image forming apparatus with anin-body paper discharge structure. The present invention can be employedfor an application where expanding a sheet discharge space isindispensable such that a paper sheet discharged on a discharge tray iseasily extracted.

DESCRIPTION OF REFERENCE SIGNS

-   A image forming apparatus-   1 exposure unit-   2 developing unit-   3 photosensitive drum-   4 cleaning unit-   5 charging unit-   6 intermediate transfer belt unit-   7 fixing unit-   8 toner cartridge unit-   10 apparatus main body-   11 image capturing housing unit (housing of image reading unit)-   11 a sidewall-   11 b slit portion-   12 image forming housing unit (housing of image forming unit)-   13 in-body paper discharge space portion-   13 a back surface-   14 conveyance roller pair-   15 prior-to-registration roller pair-   16 registration roller pair-   20 image forming unit-   21 document placement table glass-   22 scanning body-   22 a back surface-   22 b bottom surface-   23 pulling member-   24 movable wiring cable (movable wiring)-   24 a folded-back distal end portion-   26 guided portion (concaved groove portion)-   30 paper sheet conveyance system-   31 paper feed tray-   32 paper feeder-   32 a separation conveyance roller-   32 b separating member-   33 feed roller-   34 rotating plate-   35 elevating mechanism unit-   40 discharge tray-   41 discharge roller pair-   42 paper sheet discharge port (discharge unit)-   50 bottom surface (bottom surface of image capturing housing unit)-   51 first surface-   52 second surface-   53 stepped portion-   54 projection-   54 a concaved groove portion-   56 rib piece-   57 static eliminating brush-   61 intermediate transfer belt-   62 intermediate transfer belt drive roller-   63 intermediate transfer belt driven roller-   64 intermediate transfer roller-   65 intermediate transfer belt cleaning unit-   66 transfer roller-   71 hot roller-   72 pressure roller-   P paper sheet-   S paper sheet conveyance passage-   Sr front-back reverse path-   X sub-scanning direction-   Y paper discharging direction

The invention claimed is:
 1. An image forming apparatus, comprising: animage reading section configured to read a document placed on a documentplacement table by moving and scanning of a scanning body in asub-scanning direction; and an image forming section configured to forman image read by the image reading section on a paper sheet; wherein: anin-body paper discharge space is formed between the image readingsection and the image forming section and opens to a front surface sideof an apparatus main body, and a discharge section configured todischarge the paper sheet on which an image is formed by the imageforming section; and a discharge tray situated in the in-body paperdischarge space and on which the paper sheet from the discharge sectionis to be placed, the discharge tray comprising wall surfaces at bothsides of the discharge tray; a bottom surface of the image readingsection at a front surface side of the image forming apparatus in thein-body paper discharge space includes a plurality of ribs extending ina paper discharging direction; the plurality of ribs are formed atdifferent intervals.
 2. The image forming apparatus according to claim1, wherein the discharge section discharges the paper sheet from a backsurface side to the front surface side of the apparatus main body. 3.The image forming apparatus according to claim 1, wherein a lowersurface at the front surface side of the apparatus main body of theimage reading section is formed to an inclined surface.
 4. The imageforming apparatus according to claim 1, wherein the paper dischargingdirection is perpendicular to the sub-scanning direction.
 5. The imageforming apparatus according to claim 1, wherein the discharge traycomprises a flat surface without a projection.
 6. The image formingapparatus according to claim 5, wherein the wall surfaces formed at bothsides of the discharge tray extend from the discharge section to thefront surface side of the image forming apparatus.
 7. The image formingapparatus according to claim 1, wherein the plurality of ribs extend tothe front side of the discharge section in the discharging direction.